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Best known for their role in beer brewing, the female flowers of hop are being increasingly used in supplements for insomnia, anxiety, and menopausal symptoms. In addition, research on their components has revealed new activities with promising clinical applications. Read below to learn more about hops’ components, health benefits, side effects, and interactions with drugs and other herbal supplements.

What Are Hops?

Hops are the female flowers of hop (Humuluslupulus L.), a climbing plant belonging to the same family as hemp (Cannabaceae). Hop most likely originated in China, Southern Caucasus, and Siberia, or Mesopotamia, from where it spread to Japan, America, and Central Europe [R, R].

Due to its role in beer brewing, which accounts for 98% of its use, hop is nowadays cultivated in all warmer regions. The different compounds in hops add a bitter flavor to beer, prevent the growth of unwanted microorganisms during the brewing process, and stabilize foam [R].

Hops have long been used in traditional medicine, especially for [R, R]:

Hops Components

The main active components of hop are found in the female flowers. Volatile oils, bitter acids, and prenylflavonoids are produced by hair-shaped glands, while the rest of flavonoid types are most abundant in seeds and specialized leaves [R, R].

The volatile oils of hops (0.3-1% of hops weight) are very rich in terpenoids, especially [R, R]:

Although to a lower extent than in hops, active compounds can also be found in other parts of the hop plant such as male flowers (xanthohumol and bitter acids) and leaves (xanthohumol, volatile compounds, and bitter acids) [R, R].

Health Benefits of Hops

1) Hops Improve Menopausal Symptoms

Menopause is the cessation of menstrual cycles in women. It is accompanied by a reduction in female sex hormone levels, which causes symptoms such as [R]:

Hot flashes

Night Sweats

Sleep disturbances

Fatigue

Mood changes (depression, irritability)

Bone and muscle mass loss

Reduced sex drive

Vaginal dryness

The intake of hops extract or its component 8-prenylnaringenin improved these symptoms and life quality in three randomized studies on 223 menopausal women [R, R, R].

In a pilot study of 100 women, the application of a gel containing a hops extract reduced vaginal dryness [R].

2) Hops May Help Anxiety and Mood Disorders

In a study on 36 people with at least mild depression, stress, or anxiety, the intake of hops extract improved all the symptoms [R].

In rats, hops extract had antidepressant activity measured as a reduction of the time that rats spent floating immobile in a cylinder filled with water [R].

3) Hops May Help Sleep Onset (via sedative effects)

In a clinical trial on 17 people, the intake of a bit more than 1 cup (333 mL) of non-alcoholic beer improved sleep quality. Hop was suggested as the main beer component responsible for this effect [R].

Hops extract increased sleeping time and reduced physical activity and body temperature in mice and rats taking sedatives. In a study in quails, whose sleep-wake rhythm is very similar to that of humans, a dose of 2 mg hops extract was most effective in reducing night activity while preserving a normal circadian activity/rest rhythm [R, R, R, R].

Hops are frequently combined with valerian to fight insomnia. In three studies on 256 people, this combination was more effective than placebo. Two of them showed that the combination was also more effective than valerian alone [R, R, R].

Similarly, the combination of hops, valerian, and purple passionflower was as effective as the drug zolpidem in a study done on 78 people with insomnia (DB-RCT) [R].

However, two studies done on 271 people (DB-RCT) found no effects on sleep quality [R, R].

4) Hops May Help Weight Loss and Metabolic Health

In a study on 200 healthy overweight people (DB-RCT), the intake of hops extract reduced body fat, especially in the belly [R].

Xanthohumol also reduced the development, growth, and fat accumulation of fat cells while increasing their death rate [R, R].

The combination of hops isohumulones and acacia proanthocyanidins improves several symptoms of metabolic syndrome. Together with diet changes and physical exercise, it decreased blood levels of triglycerides and cholesterol (total, LDL, APOB) in a randomized trial on 23 people. The combination also reduced insulin levels while increasing insulin sensitivity in a study on 91 people (DB-RCT) [R, R].

5) Hops May Improve Dental Health

In 2 studies on 57 people, hops polyphenols (taken either as a mouth rinse or as 7- and 20-mg tablets) reduced dental plaque growth [R, R].

Hops polyphenols reduced the capacity of two bacterial species (Streptococcusmutans and Streptococcus sobrinus) to cause cavities [R].

In two studies on human gum cells, the addition of hops polyphenols blocked the inflammatory response triggered by the gum disease microbe (Porphyromonasgingivalis) [R, R, R].

6) Hops May Help Fight Allergies

In a randomized trial on 39 people with allergies to pollen, the intake of 100 mg hop extract improved nose swelling, nose color, discharge amount, and discharge characteristics [R].

In a study on human nose cells, hops water extract reduced the production of a cytokine that activates allergic inflammatory responses (TSLP) [R].

7) Hops May Improve Heart Health

In a study on 23 people (DB-RCT), the intake of hops isohumulones improved blood flow, both in smokers and non-smokers [R].

In two studies in mice, xanthohumol prevented and reversed the buildup of triglyceride and cholesterol plaques inside the arteries [R, R].

In rats, hops extract relaxed blood vessels, which may reduce the risk of heart disease [R].

After injuries, vessels can be narrowed from blood vessel cell growth and lead to heart disease. Xanthohumol was able to mitigate these effects [R, R].

Because xanthohumol inhibits platelet activity, it may reduce the risk of blood clot formation (thrombosis) [R].

8) Hops Help Blood Sugar Balance

In a study of 20 diabetic people (DB-RCT), the intake of hops isohumulones reduced blood sugar levels [R].

In multiple studies with mice and rats, the intake of hops extract, its components xanthohumol and isohumulones, or a mixture of hops isohumulones and acacia proanthocyanidins reduced blood sugar levels and insulin resistance [R, R, R, R, R, R].

Mechanism

The simultaneous activation of PPAR-alpha and PPAR-gamma by isohumulones lowers blood sugar levels by reducing insulin resistance. Hops bitter acids also activate the bitter taste receptors and stimulate the production of GLP-1, a protein that triggers insulin production in response to sugar [R, R].

9) Hops can be used as a Deodorant

In a study of 42 people (SB-RCT), hops extract mixed with an odor adsorbent agent commonly found in commercial deodorants reduced underarm odor without causing irritation. In the same study, hops extract reduced the growth of two bacterial species responsible for underarm odor (Corynebacteriumxerosis and Staphylococcus epidermidis) [R].

Hop’s xanthohumol enhanced the activity of interferon alpha (IFN-α) against a cow virus. Because this virus is very similar to hepatitis C virus, xanthohumol could be used to develop new therapies against it [R].

Xanthohumol also reduced HIV replication, the production of a virus, and the damage caused to cells. For these reasons, its investigation as a new therapeutic agent for HIV was suggested [R].

Several hops components, especially xanthohumol, were active against the parasite causing malaria (Plasmodiumfalciparum) in two cell studies [R, R].

In a study in which five hop components were tested against four human fungal pathogens (Trichophyton mentagrophytes, Trichophyton rubrum, Candida albicans, and Mucor rouxianus), xanthohumol, isoxanthohumol, and 6-isopentenylnaringenin were identified as the most powerful antifungal agents [R].

It’s important to note that no clinical trials have been done in humans infected with these pathogens, so it’s unknown if hops can kill any infection when ingested in normal doses.

Both types of bitter acids (humulones and lupulones) blocked the growth and migration of liver cancer cells, while only lupulone showed activity against skin cancer [R, R].

It’s important to note that no clinical trials have been done, so the anti-cancer effect in humans are still unknown.

12) Hops May Possibly Help With Neurodegenerative Diseases (in animals)

Hops extract reduced brain damage and maintained brain function in rats with stroke or poisoned with aluminum nitrate. The long-term intake of hops extract reduced the buildup of a protein believed to cause Alzheimer’s disease (β-amyloid) in the brain of old mice and preserved their cognitive functions [R, R, R].

Because xanthohumol (among other flavonoids) can block an enzyme involved in the onset of Alzheimer’s disease (BACE1), it was suggested as a preventive therapeutic candidate for this disease [R].

13) Hops May Improve Skin Health (in animals)

The intake of hops extract or its components xanthohumol and lupulone reduced skin inflammation (measured as ear swelling) in three studies on mice with mite-induced dermatitis, contact allergic dermatitis, and exposed to a tumor promoter agent [R, R, R].

In an antimicrobial study, xanthohumol and lupulones reduced the growth of five microbes that cause acne (Propionibacterium acnes, Staphylococcus epidermidis, Staphylococcus aureus, Kocuria rhizophila, and Staphylococcus pyogenes). Hops compounds also blocked two activities of these bacteria that also contribute to the development of acne (anti-collagenase and oxidative) [R].

14) Hops May Prevent Liver Damage (in animals)

In several mice studies, hops or its components xanthohumol and isohumulones had protective effects against the following liver disorders:

15) Hops and Digestive Function (in animals)

In a study in pigs, the supplementation of the diet with hops (or a grape product also rich in polyphenols) increased weight gain per feed intake. The new diet did not change gut morphology or feed digestibility, but changed the gut microbial composition and reduced the production of pro-inflammatory proteins [R].

In a study in thyroid-derived cells, xanthohumol improved iodide uptake, which is an essential step in the production of the thyroid hormone. In another study, xanthohumol increased TSH and activity of the enzyme that converts T4 to T3 (type 1 deiodinase) [R, R].

However, the dosages in these studies were much higher than what humans would take.

17) Pain and Inflammation

A combination of hops isohumulones, rosemary extract, and oleanolic acid reduced the pain caused by arthritis and fibromylagia in a pilot study on 54 people [R].

Mechanisms of Action

1) Female Sex Hormone Mechanisms

Some plant substances are called phytoestrogens because they can interact with female sex hormone (estrogen) receptors and trigger some of their responses. The main phytoestrogen found in hops is 8-prenylnaringenin [R, R].

Female sex hormones are recognized by two kinds of cell receptors [R]:

ERα: Mostly present in the inner layer of the uterus (endometrium), ovaries, bones, and breast glands

ERβ: Most common in fatty tissue, the inner lining of blood vessels (endothelium), brain, kidneys, and prostate

Although most phytoestrogens preferentially bind to ERβ, 8-prenylnaringenin binds to ERα. In the tissues where this receptor is found, 8-prenylnaringenin caused the following effects in animal studies [R, R]:

In mice, both α– and β-bitter acids had antidepressant activity and increased the sedative effect of ketamine but they differed in their effect on sleepiness induced by pentobarbital. While α-acids enhanced its effect, β-acids reduced it. Only β-acids reduced the activity of GABA [R, R, R].

Although xanthohumol stimulates the binding of GABA to its receptors, it failed to reduce anxiety in a study in rats [R, R].

A fixed valerian-hops combination promoted sleepiness by binding to four different types of receptors:

Reducing the production of a chemokine receptors (CXCR4) [R] and cell attachment proteins (ICAM-1) [R]

These anticancer effects have been studied in cells and animals at high dosages, but often this doesn’t translate to benefits in humans, especially at normal dosages.

4) Antioxidant Mechanisms

Reactive oxygen species are formed through chemical reactions in the body and cause oxidative damage to DNA, proteins, and fatty molecules. Plant flavonoids prevent the oxidative damage of reactive oxygen species by [R, R]:

Breaking them down

Blocking the enzymes that produce them

Retaining the minerals required for their production

Xanthohumol and other hops flavonoids activate the following antioxidant proteins:

Xanthohumol blocks a key enzyme in triglyceride production (diacylglycerol acyltransferase) and the protein that binds newly formed triglycerides to lipoproteins (MTP). This results in a decreased release of the lipoprotein that transports triglycerides through blood (apolipoprotein B) [R, R, R, R].

Xanthohumol also reduces cholesterol buildup inside the arteries by preventing damage to LDL and blocking the protein that transports this fatty molecule from HDL to LDL (cholesteryl ester transfer protein) [R, R, R].

Xanthohumol reduces the development and stimulates the death of fatty cells by reducing PPAR-gamma levels in fat cells, which lowers total body fat accumulation. In turn, isohumulones reduce blood triglyceride levels by activating PPARα. In the liver, xanthohumol prevents triglyceride buildup by binding to the farnesoid X receptor (FXR), which decreases the levels of an enzyme that promotes fat production and fatty cell development (SRBEP1c) [R, R, R, R].

7) Sugar-Lowering Mechanisms

The simultaneous activation of PPAR-alpha and PPAR-gamma by isohumulones lowers blood sugar levels by reducing insulin resistance. Hops bitter acids also activate the bitter taste receptors and stimulate the production of GLP-1, a protein that triggers insulin production in response to sugar [R, R].

Additionally, exposure to hops can cause other allergic symptoms such as [R+, R+, R]:

Contact dermatitis

Skin redness

Fluid buildup in the eyelids

Conjunctivitis

Due to the lack of studies investigating its effects, hops extract should not be used by children younger than 3 years old or women who are pregnant or breastfeeding.

Although hops 8-prenylnaringenin has proven anticancer activity, it may stimulate the growth of tumors with female sex hormone receptors (estrogen-positive) and interfere with some breast cancer therapies due to its capacity to bind to estrogen receptors. People with a history of estrogen-positive cancer or receiving breast cancer therapy should contact their doctors before taking hops extract [R, R, R, R].

Hops 8-prenylnaringenin alters the production and effects of female sex hormones, which can lead to fertility problems in premenopausal women. Therefore, young women may want to avoid high dosages of phytoestrogen supplements over extended periods [R].

Limitations and Caveats

Although they have also been tested in animals and cells, only one clinical trial on a small sample size (17-42 people) supports each of the following health benefits of hops:

Therefore, more clinical trials involving larger amounts of people are required to confirm these claims.

Although doses of up to 239 mg hops extract per day during 7-day periods caused no toxicity symptoms, no long-term toxicity studies have been carried out [R].

Drug Interactions

The hops compounds xanthohumol and lupulone increased the antibacterial power of the following antibiotics [R]:

Polymyxin

Ciprofloxacin

Tobramycin

In a study in rats, xanthohumol increased the effect of midazolam in reducing anxiety [R].

In a study in mice, the extracts of two hop varieties (Aroma and Magnum) reduced the hypnotic effect of pentobarbital and diazepam. In both cases, Magnum was the variety with the strongest effect [R].

In another study, the excitatory effect of cocaine (measured by spontaneous movement) was totally blocked by Magnum and partially blocked by wild plant extract. Aroma, Magnum, and wild plant extracts stimulated the pain-relief effect of Tylenol, with Aroma showing a stronger activity than the other two. Hops extract was found to enhance the effects of Tylenol by slowing down its breakdown in the liver [R, R].

Due to its sedative effect, hops extract should not be mixed with alcohol or with other medications causing sleepiness, such as [R, R]:

Clonazepam

Lorazepam

Phenobarbital

Zolpidem

Propofol

Hops may increase the effect of several drugs in the body by blocking the following cytochrome P450 enzymes that break them down [R, R]:

Genetics/Genetic Predispositions

In the liver and intestine, the enzyme CYP1A2 produces 8-prenylnaringenin from xanthohumol and isoxanthohumol, while CYP2C8 and CYP2C19 convert 8-prenylnaringenin and isoxanthohumol to other compounds with lower female sex hormone activity. People with mutant variants of these proteins may experience increased or reduced female sex hormone effects of hops [R].

Mutated versions of Akt, Bcl-2, mTOR, aromatase, and STAT3 that change their capacity to bind to xanthohumol may increase or reduce the anticancer effect of this hops component [R, R, R, R].

Similarly, mutated variants of NF-κB, COX1, and COX2 may be more or less susceptible to blocking by hops components and thus alter their anti-inflammatory effects [R, R, R].

The antioxidant effect of hops extract can be altered in people with mutated versions of Nrf2 and NQO1 that change the capacity of these proteins to bind to hops flavonoids [R, R].

Mutant variants of PPARα and PPARγ may have increased or reduced capacity to bind to lupulones. Similarly, mutated farnesoid X receptor versions may have altered capacity to bind to xanthohumol. In both cases, this may alter their effects on blood sugar and fatty molecule levels [R, R].

Dosage and Toxicity

The recommended dose for mood disorders such as anxiety, restlessness, and depression is 200 mg hops extract 2x/day [R].

Based on their long-term use in brewing and traditional medicine, hops are generally recognized as safe [R].

A standardized hops extract (21 mg xanthohumol, 1.3 mg 6-prenylnaringenin, 0.8 mg isoxanthohumol, 0.25 mg 8-prenylnaringenin) taken up to 4x/day for one week had no toxicity signs in a study on 5 postmenopausal women [R].

In rats, a study found no adverse effects derived from the intake of up to 4000 mg hops extract/ kg body weight per day. However, high xanthohumol doses (0.5% of diet or 1000 mg/kg body weight) reduced liver weight and breast gland development in another study. Males taking xanthohumol before mating had a higher proportion of male offspring [R, R].

User Experiences

Most people took hops supplements for insomnia and anxiety. Users were generally happy with the results and reported being able to sleep longer and feeling more relaxed without experiencing side effects such as drowsiness.

Dissatisfied users complained that the supplement had little or no effect. Only one male user reported mild unwanted female sex hormone effects, which he didn’t describe.

A few users took hops supplements to reduce inflammation and pain. They all reported satisfactory outcomes.

Despite the lack of scientific evidence to back this claim [R, R], two users reported satisfactory results when using hops extract for breast enlargement.

FDA Compliance

The information on this website has not been evaluated by the Food & Drug Administration or any other medical body. We do not aim to diagnose, treat, cure or prevent any illness or disease. Information is shared for educational purposes only. You must consult your doctor before acting on any content on this website, especially if you are pregnant, nursing, taking medication, or have a medical condition.

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JOE COHEN

CEO, SelfHacked

About Joe

Growing up, Joe was plagued with a myriad of health issues such as gut problems, autoimmune issues, chronic fatigue, brain fog, insomnia, and general inflammation. Both conventional and alternative doctors weren’t able to help him, so he decided to fix himself. With lots of health questions and few satisfying answers, Joe decided to read every research paper he could get his hands on and conduct thousands of experiments on his own body in order to fix his health issues. Joe started SelfHacked in late 2013 when he successfully fixed all of his issues, and now it gets millions of readers a month looking to educate themselves about how they can improve their health. Joe is now a thriving author, speaker, and serial entrepreneur, founding SelfDecode & LabTestAnalyzer.

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